Question: Why do birds that can't fly still have wings?

Rupert Marshall answered on 16 Mar 2017:

Birds are defined by the fact they have wings. Some birds flew to places where they didn’t need wings, like because there were no animals there that would chase them so they didn’t need to fly to escape. Penguins now use their wings to help them swim – they are brilliant swimmers! If you sit on the sofa a long time your legs don’t fall off. Same with birds and their wings. But animals need to save energy and be efficient. If big wings just get caught on bushes or stop you doing something more important then birds with smaller wings will survive better – and over thousands of years animals we end up with birds with smaller wings.